In one form of conventional earth ripper, a ripper tip is mounted to a shank which is pivotally mounted to the tractor beam by a shank pivot pin. As a result of side loads acting on the ripper during the ripping operation, the shank pivot pins have worn so that the pins, at times, were lost during the ripping operation, presenting serious safety and maintenance problems.
A number of different pivoting arrangements have been utilized in connection with such ripping devices. Illustratively, in U.S. Pat. No. 2,797,629 of Carlton O. Kelly, a pivoted shank subsoil contour plow is shown wherein the distal tips of the plow blades are disposed directly below and in vertical alignment with the pivot pin mounting the blades to a frame member so as to prevent side draft at the tips of the plows.
Donald J. Larson, in U.S. Pat. No. 2,998,965, which patent is owned by the assignee hereof, shows a push block for a tractor-mounted ripper mounted to a tractor by a pair of draft arms. The ripper shank is provided with a ripper tip and connected with the tractor beam by a clevis pivotally connected to the beam by a clevis pin. The ripper tip is spaced substantially rearwardly of the axis of the clevis pin.
In U.S. Pat. No. 3,031,175 of Mack Wooldridge, a ripper mounting for twin crawlers is shown wherein the ripper tip is spaced rearwardly of the vertical axis of the clevis pin.
Albert G. Bodine shows a sonic rectifier coupling for rock cutting apparatus in U.S. Pat. No. 3,367,716, wherein an impact device is engageable with an impact surface of the ripper shank at an angle thereto.
In U.S. Pat. No. 3,770,322, Delwin E. Cobb et al show an apparatus for fracture of material in situ with stored inertial energy which is cyclically delivered on demand to the work tool, and which energy is stored in a large flywheel and delivered to the tool by suitable transmission means. The single pivot point disclosed by Cobb et al is indicated as preferably located ahead of the cutting tip to obtain the desired motion.
Darrel M. Wooldridge, in U.S. Pat. No. 4,044,838, shows an automatic control for a ripper tool which is disposed substantially rearwardly of the majority of the mounting pins of the assembly.